A proteomic approach to investigate immunity against R. Equi in foals.
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Actinomycetales Infections↗
Biomedical subjects
L Bonizzi
Publications and source records attributed to L Bonizzi.
Transition cow: non-specific immune response.
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Animals↗
Diagnosis of Mycobacterium bovis infection in calves sensitized by mycobacteria of the avium/intracellulare group.
Because of the frequent exposure of cattle to mycobacteria of the avium/intracellulare group, an investigation was carried out into the possible repercussions thereof on the diagnosis of bovine tuberculosis. Three calves from a bovine tuberculosis-free herd, scored avian reactors in the gamma-interferon assay for bovine tuberculosis, were sedated and inoculated endotracheally with a virulent Mycobacterium bovis strain. Then, three other avian reactors were housed with the above donor calves. Mycobacterium bovis was isolated from the nasal swabs of the three endotracheally infected, donor calves. On these samples, TB complex-specific polymerase chain reaction (PCR) tests for IS6110 were also positive, albeit with a different time kinetics. The three contact-infected calves showed clear immunological signs of infection; however, their nasal swabs were always PCR-negative and only Mycobacterium avium was isolated. In the endotracheally infected donor calves there was a rise of the gamma-interferon responses to avian and bovine purified protein derivative (PPD) tuberculins, which reached the same stable plateau levels over the whole experiment. The above effect was also observed in the contact-infected calves, even though the response to avian PPD tuberculin always remained at a higher level. By using conventional bovine and avian PPD tuberculins, the comparative intradermal test was generally positive in endotracheally infected, as opposed to contact-infected calves; a positive intradermal test for M. bovis was obtained in two contact-infected calves by different bovine PPD tuberculins based on M. bovis bacillus Calmette-Guerin (BCG) secreted or somatic antigens. It was concluded that M. bovis infection may be concealed for some time in cattle sensitized by mycobacteria of the avium/intracellulare group and that different diagnostic procedures should be adopted for such animals.
Animals↗
Evaluation of the specificity of the gamma-interferon test in Italian bovine tuberculosis-free herds.
We investigated the specificity of the gamma-interferon test for bovine tuberculosis (TB) in 1,557 cattle in 30 paratuberculosis-free and officially certified TB-free dairy herds, located in three provinces of the Lombardy Region in Northern Italy. The TB-free status of the herds under examination was further confirmed by the tuberculin skin test, by an antibody assay and by post mortem examination of animals culled from the herds during the study period. The specificity of the gamma-interferon tests after a single test and a double sampling scheme were 88.8% and 95.4%, respectively. After a single test, 11.7% of dubious reactors were also detected, while most cattle (47.4%) were shown to be avian reactors, probably due to contamination from infected birds and/or forage. There was strong evidence that the specificity of the test could be related to the animals' interaction with environmental mycobacteria and/or ageing. To reduce the percentage of nonspecific bovine reactors under alleged TB-free conditions, test procedures might involve the use of more specific antigens and/or different reaction thresholds.
Animals↗
Pseudotuberculosis in marmosets, tamarins, and Goeldi's monkeys (Callithrichidae/Callimiconidae) housed at a European zoo.
Yersinia pseudotuberculosis is an insidious bacterial infectious agent distributed worldwide and endemic to European countries. It has caused several animal deaths and may threaten the effectiveness of breeding projects for endangered species. In this retrospective study, we examine the prevalence of pseudotuberculosis in Jersey Zoo (Channel Islands, U.K.) over a period of 16 yr to obtain information that can be applied to prevent the infection. The efforts made to control the disease through vaccination are also explored. Our results show that pseudotuberculosis has been endemic to Jersey Zoo since 1979 and is responsible for significant animal loss in the Callithrichidae/Callimiconidae group. Mortality due to Y. pseudotuberculosis was seasonal; a high percentage of deaths occurred during wet and cold seasons. No significant difference was found in mortality rates of vaccinated versus nonvaccinated animals. Although the efficacy of vaccination has not been confirmed, we believe that an improved vaccination program could be an important tool in controlling outbreaks of infection in marmosets and tamarins.
Animals↗
Molecular characterization of a variant of proviral bovine leukaemia virus (BLV).
Southern-blot hybridization and partial sequencing of the pol and env genes were used to characterize BLV-integrated provirus of seropositive cattle from two dairy herds in northern Italy. Comparison of the data obtained with those of previously characterized BLV strains from other geographic areas (Australia, Belgium, Japan and USA) revealed the presence of a viral variant (BLV-12), which showed both conserved and unique features. Regarding the gp51 envelope glycoprotein, the BLV-12 variant showed: 1. A high extent of conservation, which included potential glycosylation sites and cysteine residues; 2. Three unique amino acid residues not present in any of the other BLV strains analysed; and 3. Some variability at the level of one (G) of the three (F, G and H) conformational epitopes, which is probably important in the process of infection. These results agree with the suggestion that the sequence variability of the gp51 glycoprotein preferentially involves structures whose change is thought to underlie the phenomenon of escape from immune surveillance.
Amino Acid Sequence↗
Seroepidemiological and clinical survey of feline immunodeficiency virus infection in northern Italy.
Four hundred and thirty-nine feline serum samples from cats with different living conditions in the north of Italy were tested for antibodies to feline immunodeficiency virus (FIV) and for antigen of Feline Leukemia Virus by enzyme-linked immunosorbent assay. A Western blot technique was also used on the positive sera in order to confirm the presence of specific antibodies to FIV. The Western blot enabled the detection of a false positive serum. The prevalence of FIV infection in this population was 12.5% and among the seropositive cats a greater proportion was male (74.5%) than female (25.5%). A correlation between the clinical status and the evolution of the pathology is described together with a score based on the severity of the stomatitis in infected cats. The Western blot patterns of positive samples were then compared with the stage of the pathology. Statistical analysis on the distribution of FIV in stray cats, cats with garden and courtyard access and strictly house-confined cats showed a highly significant risk of the infection in the first group.
Animals↗
Lack of stereospecificity of suid pseudorabies virus thymidine kinase.
We have partially purified suid pseudorabies virus (PRV) thymidine kinase from infected thymidine kinase- mouse cells, and cytosolic swine thymidine kinase from lymphatic glands, and we have found that PRV thymidine kinase, unlike the host enzyme, shows no stereospecificity for D- and L-beta-nucleosides. In vitro, unnatural L-enantiomers, except L-deoxycytidine, function as specific inhibitors for the viral enzyme in the order: L-thymidine >> L-deoxyguanosine > L-deoxyuridine > L-deoxyadenosine. Contrary to human and swine thymidine kinases and like herpes simplex virus-1 and -2 thymidine kinases, PRV thymidine kinase phosphorylates both the natural (D-) and the unnatural (L-) thymidine enantiomers to their corresponding monophosphates with comparable efficiency. The kinetic parameters Vmax/Km for D- and L-thymidine are 3.7 and 2.3 respectively. Our results demonstrate that the lack of stereospecificity might be a common feature of the thymidine kinases that are encoded by human and animal herpes viruses. These observations could lead to the development of a novel class of antiviral drugs.
Binding, Competitive↗
Detection of bovine leukaemia virus (BLV) infection by DNA probe technology.
Classical serological methods and Southern blot hybridization for the diagnosis of bovine leukaemia virus (BLV) infection have been compared during the first nine months of life of offspring from BLV serum-negative and serum-positive dams belonging to a Friesian dairy herd in Italy. At birth, 9/13 calves analysed showed serum positivity for anti-gp60 BLV antibodies by agar immunodiffusion and/or by ELISA. However, only two calves were positive for BLV integrated proviruses in their lymphocyte DNA. At six months of age, anti-gp60 BLV antibodies and proviral DNA positivities were simultaneously shown only by the two cattle identified as DNA-positive at birth. This pattern remained constant up to nine months of age. Furthermore, analysis of the molecular characteristics of BLV integrated proviruses, carried out by using, as probes, the almost complete proviral genome (Belgian isolate) or a subclone of the env gene radioactively labelled or chemically modified, revealed that the calves under study were infected by a different isolate (Japanese isolate) and that, in one of the cattle, the majority of integrated proviruses was characterized by deletions probably located in the 5' half of the proviral genome.
Animals↗
Characterization of some parameters of non-specific immunity in dairy cattle (I).
The concentrations of serum protein and immunoglobulin, complement, lysozyme, serum bactericidal activity and blast transformation of peripheral blood lymphocytes were assessed in dairy cattle in different herds and age groups. The study aimed at defining fundamental aspects of non-specific defence under the field conditions, related to age/season/management influences. The observed differences in the expression of these parameters are discussed, with regard to their role in the immune defence of calves and their relation to colostrum uptake. The possible use of these parameters in the control of animal welfare is stressed and the possibility is put forward of predicting possible unfavourable interactions with environmental pathogens.
Animals↗
Characterization of some parameters of non-specific immunity in beef cattle (II).
Serum protein, immunoglobulins, complement, lysozyme, serum bactericidal activity and blast transformation of peripheral blood lymphocytes were tested in beef cattle in different herds and age groups. These parameters were evaluated in their time-kinetics, in comparison with age-matched groups of dairy cattle. Like dairy calves, beef calves up to 4 months of age were shown to have low levels of serum bactericidal activity and haemolytic complement; besides, a worse profile was detected in serum protein and gamma 2 globulin levels. Al(OH)3 and oil-adjuvanted vaccines had a favourable influence on immunoglobulin and lysozyme synthesis. An acute stressing event like transportation was shown to decrease mitogen-driven lymphocyte stimulation for at least 10 days after arrival.
Animals↗
Stimulation of the antibody response after treatment with thymomodulin in mice immunodepressed with cyclophosphamide and in aging mice.
The capacity of Thymomodulin, a thymic derivative, to restore the antibody response and the number of circulating leucocytes in immunodepressed animals was studied. Administered daily to cyclophosphamide-treated mice, Thymomodulin significantly stimulated the recovery of the antibody response to sheep erythrocytes after a second administration of the antigen. The white blood cell count also showed a rapid and significant increase. Antibody titres were enhanced to normal range values again in immunodepressed rabbits. The possible mechanism of these findings is discussed. Some preliminary results obtained in restoring the immune response in aged mice are also reported.
Aging↗
Preparation of immobilized NAD glycohydrolase from Neurospora crassa conidia by hydrophobic interaction--characteristics of the enzyme derivative.
NAD glycohydrolase from Neurospora crassa conidia has been immobilized by hydrophobic interaction on Sepharose 4B beads coated with propyl residues through CNBr activation. The bond resulted stable under a wide range of conditions (ionic strength, temperature, pH). As a result of immobilization the pH optimum for catalytic activity shifted by about 0.2 pH unit in the acidic direction, to lie between 7.5 and 7.3. The stability of the enzymatic activity was largely enhanced by effect of immobilization but the Km value towards NAD+ was increased compared with that of the free enzyme (1 X 10(-3) and 2 X 10(-4) M respectively).
Catalysis↗
Biological activities of interleukin-2 and gamma-interferon in bovine T lymphocyte conditioned media.
Interleukin 2 and gamma-interferon were revealed in cultures of Concanavalin A-activated bovine mononuclear cells from peripheral blood leukocytes and their kinetics of production were described. Cyclosporin A could dramatically inhibit the synthesis of interleukin 2, whereas it did not affect the interleukin 2-dependent proliferation of bovine T blasts. Bovine T lymphocyte conditioned media (TLCM) containing gamma-interferon increased the expression of beta-2 microglobulin in human HEL (Human Embryo Lung) 299 cells and exerted a potent anti-proliferative effect upon bovine Aubek cells. The beta-2 microglobulin modulating activity of bovine gamma-interferon was exerted at very low concentrations, which showed no detectable antiviral activity on human cells.
Animals↗
Aphidicolin inhibits in vitro the activity of pseudorabies virus (PRV) DNA polymerase and in vivo the viral proliferation.
We have purified and characterized Pseudorabies virus (PRV) DNA polymerase from infected TK- mouse cells. PRV DNA polymerase has a 3'- > 5' exonuclease activity; it is stimulated by ionic strength, requires magnesium for optimal activity and it is more sensitive to aphidicolin than eukaryotic and HSV-1 replicative DNA polymerases. Aphidicolin inhibits in vitro PRV DNA polymerase competitively with respect to dCTP with a Ki of 0.06 microM and completely blocks viral growth in vivo at 4.4 microM. The high sensitivity to aphidicolin of animal herpesvirus DNA polymerases might allow a topical use of this drug in the treatment of animal herpesvirus keratitis and stomatitis.
Animals↗